Silence warnings for cygwin compiling

Hi,

Please change as below:

--- csctapi/ifd_smartreader.c
+++ csctapi/ifd_smartreader.c
@@ -900,7 +900,7 @@
 }

 #if defined(__CYGWIN__)
-static WINAPI read_callback(struct libusb_transfer *transfer)
+static void read_callback(struct libusb_transfer *transfer)
 {
 #else
 static void read_callback(struct libusb_transfer *transfer)

Thx 😃